Hydroprocessing of biocomponent feedstocks with low purity hydrogen-containing streams

Abstract

A biocomponent feedstock can be hydroprocessed using a hydrogen-containing refinery as a source of hydrogen gas. A relatively low cost catalyst, such as a water gas shift catalyst and / or spent hydrotreating catalyst, can be used as a hydrogenation catalyst for the process. The hydroprocessing can allow for olefin saturation and / or deoxygenation of the biocomponent feed by using a relatively low value refinery stream, e.g., containing from about 20 mol % to about 60 mol % hydrogen.

Description

FIELD[0001]Systems and processes are provided for hydrotreatment of biocomponent feeds using a relatively low value refinery stream as a hydrogen source.BACKGROUND[0002]Fuels based on biocomponent sources will likely become increasingly prevalent in the future. Already, various governments have instituted current and future requirements that motor fuel pools contain a minimum percentage of fuel derived from a biocomponent source, such as a plant, animal, fish, or algae-based oil or fat.[0003]Producing diesel fuel from biocomponent sources also presents a variety of challenges. In particular, for diesel hydroprocessing units that operate at low pressures, the presence of the additional heteroatoms in a biocomponent based diesel feed may pose difficulties. Modifying and / or replacing low pressure units to allow for higher processing pressures would require expensive capital investment.[0004]For production of diesel fuel, vegetable oils such as canola oil, palm oil, or other similar oil...

AI Technical Summary

Benefits of technology

[0025]In some embodiments, one of the benefits of the invention is the ability to use a relatively low value refinery source (effluent stream) to treat a new type of refinery feed. The oxygen content in a biocomponent feed can create a variety of problems in a refinery. The oxygen content can be as high as about 10-12% by weight, meaning that a large amount of hydrogen may be needed to remove the oxygen by a hydrogenation type reaction. Biocomponent feeds can also have a tendency to suppress hydrodesulfurization (HDS) activity, making co-processing of a biocomponent feed challenging. However, the oxygen removal reaction can occur under relatively mild conditions and typically will not require relatively harsh conditions. Thus, a relatively low activity hydrogenation catalyst not only can be sufficient but may also be desirable to catalyze the hydrodeoxygenation (HDO) reaction. Similarly, relatively low hydrogen partial pressures can often be sufficient to perform HDO. By using a relatively low cost catalyst and a relatively low value refinery stream for an initial processing step, the invention allows for production of a biocomponent based (diesel) product at reduced expense and with little or no significant impact on other refinery resources. In particular, significant amounts of hydrogen may not need to be diverted from another refinery operation for use in deoxygenating a biocomponent feed.

Problems solved by technology

Producing diesel fuel from biocomponent sources also presents a variety of challenges.

In particular, for diesel hydroprocessing units that operate at low pressures, the presence of the additional heteroatoms in a biocomponent based diesel feed may pose difficulties.

Modifying and / or replacing low pressure units to allow for higher processing pressures would require expensive capital investment.

Lower hydrogen pressures are mentioned as helping to reduce hydrogen consumption, but such pressures are mentioned as also leading to catalyst deactivation.

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